<!doctype html>
<meta charset="utf-8">
<title>CSS.supports</title>
<link rel="help" href="https://drafts.csswg.org/css-conditional/#dom-css-supports">
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script>
  test(function() {
    assert_equals(CSS.supports("color: red"), true);
  }, "Single-argument form allows for declarations without enclosing parentheses");

  test(function() {
    assert_equals(CSS.supports("(color: red) and (color: blue)"), true);
  }, "Complex conditions allowed");

  test(function() {
    assert_equals(CSS.supports("not (foobar)"), true);
  }, "general_enclosed still parses");

  test(function() {
    assert_equals(CSS.supports("color: something-pointless var(--foo)"), true);
  }, "Variable references always parse");

  test(function() {
    assert_equals(CSS.supports("color: something-pointless(var(--foo))"), true);
  }, "Variable references in an unknown function always parse");

  test(function() {
    assert_equals(CSS.supports("color", "red"), true);
  }, "two argument form succeeds for known property");

  test(function() {
    assert_equals(CSS.supports("unknownproperty", "blah"), false);
  }, "two argument form fails for unknown property");

  test(function() {
    assert_equals(CSS.supports("width", "blah"), false);
  }, "two argument form fails for invalid value");

  test(function() {
    assert_equals(CSS.supports("--foo", "blah"), true);
  }, "two argument form succeeds for custom property");

  test(function() {
    assert_equals(CSS.supports("selector(div)"), true);
  }, "selector() function accepts a selector");

  test(function() {
    assert_equals(CSS.supports("selector(div, div)"), false);
  }, "selector() function doesn't accept a selector list");

  test(function() {
    assert_equals(CSS.supports("selector(::-webkit-unknown-pseudo-element)"), false);
  }, "selector() function rejects unknown webkit pseudo-elements.");

  test(function() {
    assert_equals(CSS.supports("selector(::before)"), true);
  }, "selector() function accepts known pseudo-elements");

  test(function() {
    assert_equals(CSS.supports("selector(div + .c)"), true);
  }, "selector() with simple combinators");

  test(function() {
    assert_equals(CSS.supports("selector(div | .c)"), false);
  }, "selector() with unknown combinators");
</script>
